Assembly Line Production - The Process of Combining Parts in Sequence

Assembly Line Production –
Introduction
1
Dheenathayalan.R Hosur
dheena21.r@gmail.com

Definition-Assembly
• Assembly - The process of putting
together a number of parts( to make a
machine or other product).
- The act of combining components
2

Definition - Line
• Line – Is the Path and has direction
,length and thickness.
3

Definition - Production
• Production –The processes and methods
used to transform tangible inputs (raw
materials,semi-finishedgoods, subassemblies)
and intangible inputs (ideas, information,
knowledge) into goods or services.
• Tangible - real , able to be shown, touched, or experienced.
• Intangible - unable to be touched, not having physical
presence.
4

Definition
• Assembly Line Production
–is a manufacturing process in which
parts are added as the semi-finished assembly
moves from workstation to workstation where the
parts are added in sequence until the final
assembly is produced.
- is a production process that breaks
the manufacture of a good into steps that are
completed in a pre-defined sequence.
5

Principle
Assembly Line Production
The principle of an assembly line is that each worker is
assigned one very specific task, which he or she simply repeats,
and then the process moves to the next worker who does his or
her task, until the task is completed and the product is made.
It is a way to mass produce goods quickly and
efficiently.
All workers do not have to be human; robotic workers
can make up an assembly line as well.
Note:
Principle - a basic idea or rule that explains or controls how
something happens or works
6

Advantages –Assembly Line
Production
7
• Speed & Mass Production
• Fair Product Cost
• Affordable
• Uniformity of finished products
• Ease of repair
• Standardized Parts
Employee
• Specialization (in a specific task)
• Average Skill level sufficient
• Ease of job rotation
• Able to share Improvements in Process, Product
etc

Dis advantages –Assembly Line
Production
8
• Higher initial capital investment
• Inflexible Production facility
• Need of specialized machines
• Significant Space is required
Employee
• Monotonous Work (Repetitive Work)
• Missing of unique craftsmanship(Luxury items).
• Motivational problems exists
• Skill level balancing will be a problem
• Overconfidence

Production & Productivity
9
• Production - the volume of output irrespective of
the quantity or quality of resources used to attain
that level of output. Refers only to quantity
produced. Measure of produced goods.
• Productivity -If we put in it element of efficiency
with which the resources are employed, we enter
the area of productivity.(How much is produced
using what with its quantity,quality)
Measure of efficiency or rate of production.
(Output/Input)

Production & Productivity
10
• For Example consider Current Situation.
Engines Produced(Nos) = 50 Engines
Manpower utilized(Nos) =50 Men
Productivity =50Engines/50Men =1Engine/1Men
Case 1:If we increase Engines produced to 60Nos and Manpower to 60Nos.
Production has increased =from 50engines to 60 engines.
Productivity remains Same.
That is 60Engines/60Men=1Engine/1Men
Case 2:If we increase Engine produced to 60Nos and Manpower remains same
at 50 Men. Here Production and Productivity both got increased.
Production increase = from 50 Engines to 60Engines
Productivity =60Engines/50 Men=1.2Engines/Men
Case 3:If we keep engines produced same at 50Engines and reduce manpower
to 40Men.
Production remains same.
Productivity increase =50 Engines/40Men=1.25Engines/men
Case 4:If we increase engines produced to 68 Engines and increase manpower
to 56 Men.
Production has increased =from 50 engines to 68Engines.
Productivity increase =68 Engines/56Men=1.21Engines/Men

Takt Time
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• Takt – Takt means pace or rhythm.Takt was
borrowed from Taktzeit, a German word.
• Takt time is the maximum acceptable time to meet
the customer demand.
• To calculate Takt time
Takt time= Net available Time/Customer Demand
Note:Net available time is the actual time available
for doing the work.It excludes break times(Lunch
time,Tea time etc)

Takt Time
12
Example:
Total Available time/Shift=480minutes
Tea break(2times/shift) = 30minutes
Net available time=480-30= 450minutes
Demand per shift =50Engines
Takt time =450/50=9minutes/Engine
That is One engine will be produced every
9minutes.

Cycle Time
13
Cycle time - is the total time from the
beginning to the end of process.
Cycle time includes process time, during which
a unit is acted upon to bring it closer to an
output, and delay time, during which a unit of
work is spent waiting to take the next action.
Cycle time starts when the actual work begins
on the product and ends when it is ready for
delivery.

Lead Time
14
Lead Time – It is the time between order for
a product and delivery of that product.
Simply “time between order and delivery”.
Example =Time between Customer placing
an order and company deliver that order.

Difference between Cycle Time
and Lead Time
15
Consider below example
1. Customer places order on January
01,2018
2. Work started on that order by the
company on January 03,2018
3. Work completed on January 05,2018
4. Delivered to customer on January 06,2018
5. Lead time = 5Days
6. Cycle time= 2Days

Standard Time
16
Standard time - is the time required by an
average skilled operator, working at a
normal pace, to perform a specified task
using a prescribed method.
Standard time = Normal Time + Total
Allowances
Note:
Normal time = {(Time worked) / (Number
of units produced)}*(Performance rating)

Standard Time
17

Line Balancing
18
Line Balancing - is leveling the workload
across all processes in a cell or value stream
to remove bottlenecks and excess capacity.
Everyone is doing the same amount of
work.
No one is waiting.
No one is overburdened.
Variation is smoothed.

Bottle Neck
19
Bottleneck - is one process in a chain of
processes, such that its limited capacity
reduces the capacity of the whole chain.
Has Maximum Stage Time.
Significantly slows down
production.(Impacts the output).
Have More WIP(work in process)
The station that consumes more cycle time.
Limits the capacity of the system.

Bottle Neck
20

How to reduce Bottle Neck
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1. Possibility to Increase manpower.
2. Possibility to increase machine/tools.
3. Possibility to split the task and assign to
prior stage/Later stage.
4. Outsourcing-Partial/Full.
5. Automation-Semi/Full.
6. Process improvement.
7. Reduce Setup time.Eg- SMED
Note:SMED – Single -Minute Exchange of
Dies.

Assembly Line Balancing
22
Assembly line balancing - is a production
strategy that sets an intended rate of
production to produce a particular product
within a particular time frame.
That is “the work is divided in to series of
elementary tasks with short durations”.

Need- Assembly Line Balancing
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To meet customer demand.
To determine the speed of the assembly
line.
To determine the number of stages or
number of workstations.
To identify the bottleneck stage/operation.
To equalize the workload among the
employees.
To reduce production cost.

Models - Assembly Line
Balancing
24
Model 1
Tries to determine the minimum
workforce required to achieve a given desired
production rate.
Model 2
Tries to determine the maximum
production rate which can be achieved with a
given workforce.
Note:
Once the Takt time is determined we
need to relate takt time with Man time,
Machine Time & Setup time.

Time Study
25
Time Study - a work measurement technique
consisting of careful time measurement of the task with a
time measuring instrument to establish the time required
for completion of the task by a qualified worker when
working at a defined level of performance.
 It will be adjusted for any observed variance from normal effort or
pace and to allow adequate time for such items as foreign elements,
unavoidable or machine delays, rest to overcome fatigue, and
personal needs.

Motion Study
26
Motion Study -Motion study is a
systematic way of determining the best
method of doing the work.
Systematic recording and critical
examination of existing and proposed ways
of doing work as a means of developing
and applying easier and more effective
method and thereby reducing cost.

Predetermined Motion Time
System (PMTS)
27
PMTS - a procedure that analyzes any manual
activity in terms of basic or fundamental motions
required to perform it. Each of these motions is
assigned a previously established standard time
value and then the timings for the individual
motions are synthesized to obtain the total time
needed for performing the activity.
Example for PMTS –MTM,MOST, etc
MTM – Method Time Measurement
MOST - Maynard Operation Sequence Technique

MOST (Maynard Operation
Sequence Technique)
28
 MOST - is a predetermined motion time system that is used primarily in
industrial settings to set the standard time in which a worker should perform a
task.
 To calculate this, a task is broken down into individual motion elements, and
each is assigned a numerical time value in units known as time measurement
units, or TMUs, where 100,000 TMUs is equivalent to one hour.
 All the motion element times are then added together and any allowances are
added, and the result is the standard time.
 1 Hour = 100,000 TMUs
 1 TMU = 0.00001 Hours
 1 TMU = 0.036 Seconds
 1 Second = 27.8 TMUs
 Basic Sequence Models in MOST
General Move,
Controlled Move,
Tool Use

Lean Manufacturing
29
Lean manufacturing or lean production,
often simply "lean", is a systematic
method for waste minimization /
elimination (“Muda”) within a
manufacturing system without
sacrificing productivity.

Seven wastes - Lean Manufacturing
30
1. Waste of overproduction (more than what the customer wanted)
2. Waste of rework (Defective product).
3. Waste of waiting (the units should flow from one process to the
next and ultimately, to the customer without any waiting)
4. Waste of inventory (make it to order and invoice it - inventory has no
real value - a sale does!)
5. Waste of transport (reduce floor space , shrink the factory, reduce lead times)
6. Waste of motion (unnecessary movements - human)
7. Waste from the process(Over processing).
In modern times, 2 new wastes have been added
Waste of a human being (an example is a machine watcher)
Waste of natural resources (save the planet)

Value Stream Mapping(VSM)
31
 Value-stream mapping is a lean-
management method for analyzing the
current state and designing a future state for
the series of events that take a product or
service from its beginning through to the
customer .
 Toyota call it as "material- and
information-flow mapping".
 The purpose of value stream mapping is to
identify and remove or reduce "waste" in
value streams, thereby increasing the
efficiency of a given value stream.

Value Stream Mapping(VSM)
32

One(Single) Piece Flow
33
Completing the production of one unit from start
to finish with little work in process (WIP)
inventory between operations .
It is the fundamental element of becoming Lean.
The word "one" does not necessarily have a literal
meaning.
It should be related to the customers'
requirements.
Companyshould produceonly
“what,when&Howmuch“thecustomer wants.

SMED
(Single-Minute Exchange of Dies)
34
SMED - is a system for dramatically
reducing the time it takes to complete
equipment/Tool/Die changeovers.
 The name Single-Minute Exchange of Dies
comes from the goal of reducing changeover
times to the “single” digits (i.e. less than 10
minutes).
SMED was developed by Shigeo Shingo, a
Japanese industrial engineer.

Six Sigma(6σ)
35
Six Sigma is a disciplined, statistical-
based, data-driven approach and
continuous improvement methodology for
eliminating defects /reducing variation in
a product, process or service.

Six Sigma(6σ) -Methodologies
36

OEE –Overall Equipment
Effectiveness
37
OEE – an yardstick used in TPM to
measure the perfection of manufacturing
system.
OEE=Availability*Usability*Performance
Efficiency * Quality Rate * 100

5’S’
38
5S - is used to organize the workplace
well so that it motivates people to perform
well.
1. SEIRI-Sort Out(Segregate)
2. SEITON-Set in order(Arrange& Identify)
3. SEISO-Shine(Wipe & Clean)
4. SEIKETSU-Standardize
5. SHITSUKE-Sustain(Discipline)

7 QC Tools
39
1. Check Sheet
2. Cause & Effect Diagram
3. Control Chart
4. Histogram
5. Pareto Diagram
6. Scatter Diagram
7. Stratification
Note : We need to identify the right tool for
the problem.

Kaizen
40
Kaizen – Japanese word means Continuous
improvement.
Kaizen – is small improvements
systematically carried out on a continual
basis by all employees.
Principle:
Very large number of small
improvements (Value) =
Large Improvement (Value)

POKA-YOKE
41
Poka-Yoke a Japanese word is nothing but
Mistake Proofing. It is a scientific technique
used to prevent problems due to error.
 Mistakes can happen if not prevented.
 Poka-Yoke removes the possibility of
mistakes being done.
 Poka-Yoke detects an error, gives a
warning and can shut down the process.

FMEA – Failure Mode & Effect
Analysis
42
FMEA is
(1)Anticipation of potential failure modes and its effects.
(2)Identifying causes for that failure modes.
(3)Identify & recommend corrective / preventive actions to
reduce/eliminate risks due to failures.
(4)Put all controls in place.
Risk Priority Number(RPN)
=Severity*Occurrence*Detection(SOD)
RPN is used for prioritization
Types of FMEA
 System FMEA
 Design FMEA
 Process FMEA

Statistical Process Control(SPC)
Statistical process control (SPC) is a
method of quality control which
employs statistical methods to monitor and
control a process.
SPC helps to ensure that the process
operates efficiently, producing more
specification-conforming products with
less waste (rework or scrap).
43

Process Capability
Process Capability is a statistical
measurement of a process’s ability to
produce parts within specified limits on a
consistent basis.
44

Process Capability Index
Process Capability Index (Cp) is ratio of
Specified spread and actual Spread.
Process Capability Index (CpK) is a measure of
Process centering.
CpK = Minimum of { }
CpK is always less than or equal to Cp
45

Torque
Torque - Rotational energy about an axis or
pivot point.
- is a measure of the force that can
cause an object to rotate about an axis.
- Torque is used to create tension in
threaded fasteners.
46
Rotational
Force
Load
(Force)
Distance
Point of
Rotation
Torque = Force(kg or N) * Distance(m)
Unit = Kgm or Nm

Torque Wrench
Torque Wrench - a tool used to apply precisely a
specifictorquetoafastener(suchasanutorbolt).
1 Pascal = 1 N/m² = 1 (kg*m/sec²)/m²
1 kg = 9.80665 N, 1 N = 1 kg × m / s2
47

Methods of Tightening Threaded Fasteners
1. Torque control tightening.
2. Angle control tightening.(Rotation angle method)
3. Yield controlled tightening.
4. Bolt stretch method.
5. Heat tightening.
6. Use of tension indicating methods.
Torque control tightening – Bolt tightening is controlled by the torque
value. Dispersion of axial tension is wide.
(eg 100Nm)
Angle control tightening(Rotation angle method) –
Bolt tightening is controlled by the angle.
Snug torque + defined angle.
(eg 100Nm + 90±5 ̊).
Bolt is tightened within the plastic zone. Dispersion of axial tension
is small.
Snug torque - A tightening procedure in which a fastener is first tightened by a pre-
selected torque. The torque required to pull plates together so that direct
contact occurs; often used in angle control tightening. It ensures that metal to
metal contact occurs at all the interfaces within the joint.
48

Bolt/Screw/Set Screw
Bolt – is a threaded fastener, with a head, designed to
be used in conjunction with a nut. Plain shank is
present.
Screw - A headed threaded fastener that is designed to
be used in conjunction with a pre formed internal
thread or alternatively forming its own thread.
(Historically, it was a threaded fastener with the
thread running up to the head of the fastener that
has no plain shank).
Set Screw - It is a threaded member that normally does
not have a head. Various socket types are provided
to allow the set screw to be rotated. These types
include hexagon socket, fluted socket, screwdriver
slot .
49

Bolt/Screw/Set Screw
Bolt
50
Screw
Set Screw

Pneumatic (Torque) Wrench
Pneumatic (torque) wrench is a planetary torque
multiplier or a gearbox that is mated to a
pneumatic air motor. At the end of the gearbox
is a reaction device that is used to absorb
the torque and allows the tool operator to use it
with very little effort. The torque output is
adjusted by controlling the air pressure.
51

Impact wrench - (also known as impact gun, air gun) is
a socket wrench power tool designed to deliver
hightorque output withminimaleffort bythe user,by
storing energy in a rotating mass, then delivering it
suddenlytotheoutputshaft.
52

Pulse wrench - Pulse wrench (pulse tools) are
discontinuous-drive tools. They apply torque in small
increments rather than in one continuous blow. When
the fastener is running free, the tool doesn't pulse and
thedriveshaftspinsrapidly.
53

Thank You
Keep LearningDheenathayalan.R Hosur
54

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